Original plastic chrome plated interior sail panel dome lamp lens housing. This is the housing that mounts on the side of the headliner sail panel. The outside diameter is 3 1/4" and accepts the lens with 4 tab mount that is 2" diameter. Fits 69 70 71 Buick Skylark / GS models and 69 70 71 72 Cutlass / 442 models.GM # 8732783